Suspension thrust bearing with retaining means

ABSTRACT

A suspension thrust bearing including a first race, a second race, a row of rolling bodies disposed between the two races, a first cap 13 in contact with the first race, and a first cup 4 in contact with the first cap 13. The first cap 13 includes integral axial retention means for retaining the first cup 4.

[0001] The present invention relates to suspension thrust bearings usedin particular in telescopic suspension arms of steered wheels ofautomobile vehicles.

[0002] A suspension thrust bearing generally includes a top race and abottom race between which are disposed rolling bodies in the form ofballs or rollers.

[0003] The invention relates more particularly to suspension thrustbearings including at least one synthetic material cap in contact withone of the two races of the bearing.

[0004] The suspension thrust bearing is disposed at the top of thesuspension arm, between a generally metallic bottom cup, serving also asa seat for a suspension spring, and a top member fastened to the body ofthe vehicle. This is known in the art. The suspension spring isinstalled around the piston rod of the damper, the end of which isfastened to an elastic support block. The suspension thrust bearingallows rotation between the bearing cup of the spring, which can rotate,and the elastic support block, which is fixed to the body of thevehicle. The suspension thrust bearing also transmits axial forcesbetween the spring and the body of the vehicle. Relative angularmovement between the spring bearing cup and the elastic support blockresults from turning of the steered wheel and/or compression of thesuspension spring. The top race of the bearing can be equipped with ametal band bent over said race and clamped to said top member fastenedto the body of the vehicle. See French patent No. 2 665 494, forexample. However, it is difficult to control the clamping of the bandinto the housing of the top member because of manufacturing tolerances.

[0005] A device employing one or two synthetic material caps can beused, as described in the document U.S. Pat. No. 4,995,737 or EP-A-390331, each cap capping a race and having axial retaining meanscooperating with the other cap. The caps are generally made fromsynthetic material charged with glass fibers to give them the necessarystrength and stiffness. Synthetic material caps transmit and distributeforces between the bearing and the adjacent members. They alsostandardize the dimensions of the bearing races, i.e. they enable thesame races to be used for different applications merely by modifying theexternal geometry of the caps.

[0006] The invention proposes a suspension thrust bearing forming acompact assembly adapted to be easily manipulated and transportedwithout risk of accidental loss of any of its components.

[0007] The suspension thrust bearing conforming to one aspect of theinvention includes a first race, a second race, a row of rolling bodiesdisposed between the two races, a first cap in contact with the firstrace, and a first cup in contact with the first cap. The first capincludes integral axial retention means for retaining the first cup.

[0008] This provides a simple subassembly, consisting of the suspensionthrust bearing and the top cup, that cannot come apart while it is beingmanipulated and is easy to manipulate, transport and finally mount onthe vehicle.

[0009] In one embodiment of the invention the axial retention means ofthe first cap include an annular lip force-fitted over a cylindricaloutside surface or a bore of the first cup.

[0010] In another embodiment of the invention the axial retention meansof the first cap include a plurality of tongues interfering with acylindrical outside surface or a bore of the first cup.

[0011] The bearing advantageously includes a second cap in contact withthe second race. The first cap includes axial fastening means forfastening it to the second cap.

[0012] In one embodiment of the invention the axial fastening means ofthe first cap for fastening it to the second cap include an annular riband the second cap is adapted to cooperate with the rib, for exampleanother rib of complementary shape.

[0013] In one embodiment of the invention the bearing includes a secondcap fastened to the second race and a second cup in contact with thesecond cap. The second cap includes axial fastening means for fasteningit to the second cup.

[0014] In one embodiment of the invention the axial fastening means ofthe second cap for fastening it to the second cup include a plurality ofhooks interfering with a surface of the second cup.

[0015] The first and second races are advantageously made from thinsheet metal. The first and second races can consist of a simple annuluswhose cross section is circular-arc-shaped.

[0016] A suspension thrust bearing is obtained whose overall size in theaxial and radial directions is not changed compared to prior artbearings, which provides an excellent seal and which includes means forfastening its various members together.

[0017] The invention will be better understood and other advantages willbecome apparent on reading the detailed description of a few embodimentsprovided by way of non-limiting example and shown in the accompanyingdrawings, in which:

[0018]FIG. 1 is a view in axial section of an assembled suspensionthrust bearing;

[0019]FIG. 2 shows a detail from FIG. 1;

[0020]FIG. 3 shows a variant of FIG. 2;

[0021]FIG. 4 shows a detail from FIG. 3;

[0022]FIG. 5 shows a variant of FIG. 1; and

[0023]FIG. 6 shows a detail from FIG. 5.

[0024] The damper includes a cylinder in which slides a piston whosepiston rod 1 is connected at its top end to an elastic support block 2fastened to a cup 4 fixed to the chassis 3.

[0025] The top cup 4 is fixed to the chassis by bolts 5 with heads 6 incontact with the cup 4, the bolts passing through holes in said chassisand cooperating with nuts 7. The cup 4 is of annular shape and has aradial portion 4 a in contact with the chassis 3 and terminating at theoutside in a substantially cylindrical axial rim. A radial portion 4 bof smaller diameter than the portion 4 a is connected to the latter byan oblique portion so that said radial portion 4 b is spaced from thechassis 3, in other words offset axially downward. A cylindrical axialportion 4 c originating from the small diameter end of the radialportion 4 b is directed away from the chassis 3.

[0026] The generally annular elastic support block 2 is molded over thetop cup 4 and the cylindrical sleeve 9 mounted on the cylindrical end 1a of the rod 1.

[0027] The elastic support block 2 is in contact with the cylindricalportion 4 c, the radial portion 4 b and part of the oblique portionbetween the radial portions 4 a and 4 b. The elastic support block 2 isalso in contact with a portion of the external cylindrical surface 9 aof the sleeve 9.

[0028] The top end of the piston rod 1 has a portion 1 a of smallerdiameter than the remainder of the rod 1, from which it is separated byan annular radial surface 1 b. An abutment washer 8 in the form of anannular cup is mounted around the end 1 a of the rod 1 at the dampercylinder end and in contact with the radial surface 1 b. The abutmentwasher provides a seating for an elastic buffer (not shown) serving asan end of travel abutment in the event of extreme and exceptionaldisplacement of the suspension. Above the sleeve 9 are a generallyfrustoconical cup 10, a washer 11 and a nut 12 cooperating with athreaded portion of the top end 1 a to fasten together the abutmentwasher 8, the sleeve 9 and the cup 10.

[0029] There are further provided a top cap 13, a thrust bearing 14, anda bottom cap 15, these members being seen more clearly in FIG. 2, aswell as a bottom cup 16 and a suspension coil spring 17.

[0030] The bottom cup 16 is of annular shape and has a radial orslightly frustoconical portion 16 a of large diameter offering a contactsurface for the top end of the spring 17, a substantially cylindricalintermediate portion 16 b originating from the small diameter end of theportion 16 a and directed downward, away from the chassis 3, andoffering a centering surface to the spring 17, and another radialportion 16 c connected to the cylindrical portion 16 b and directedinward. The cups 4 and 16 are generally made of sheet metal and the caps13 and 15 are generally made of a synthetic material.

[0031] The top cap 13 is in contact with the bottom surface of theradial portion 4 b of the top cup 4 and with the cylindrical outsidesurface 4 d of the cylindrical portion 4 c of said cup 4. To be morespecific, the top cap 13 has a toroidal concave surface 13 a, which isopen on the side facing away from the chassis 3, and an annular groove13 b radially outside the concave surface 13 a and delimited by an axialrim 13 c formed at the large diameter end of the cap 13 and extendingdownward, away from the chassis 3. On the opposite side the top cap 13has a groove 13 d substantially adjacent the concave surface 13 a, andthen an annular rib 13 e extending radially outward, and finally anoblique lip 13 f coming into contact with the cylindrical surface 4 d ofthe portion 4 c of the top cup 4. The top cap 13 and the top cup 4 arefastened together by said lip 13 f, which forms retaining means with aclamping action. In the free state, the lip 13 f has a diameter slightlyless than the diameter of the cylindrical outside surface 4 d. The cap13 includes a bore 13 g and has a radial top surface 13 h in contactwith the radial portion 4 b of the top cup 4.

[0032] The bearing 14 includes a top race 18 of thin sheet metal havingan annular shape of toroidal cross section. The top race 18 is incontact with and espouses the shape of the toroidal concave surface 13 aof the top cap 13. The bearing further includes a bottom race 19 ofsimilar shape to the top race 18, which is particularly economical inthat the bearing comprises two strictly identical races mountedface-to-face. Between the top race 18 and bottom race 19 is a row ofrolling bodies 20, balls in this instance, and a cage 21 for maintainingthe circumferential spacing of the rolling bodies 20.

[0033] The bottom cap 15 has a toroidal concave surface 15 a of similarshape to the corresponding surface 13 a of the top cap 13 and in contactwith and espousing the shape of the bottom race 19 of the bearing 14.The top cap 13 and the bottom cap 15 transmit and distribute forcesbetween the races of the bearing 14 and the top cup 4 and the bottom cup16. The cap 15 also includes an annular rib 15 b extending axiallyupward, i.e. toward the chassis 3, and occupying the groove 13 b of thetop cap 13, thereby surrounding the bearing 14, and then an outsidecylindrical surface 15 c in contact with the cylindrical portion 16 b ofthe bottom cup 16, and a bottom radial surface 15 d in contact with theradial portion 16 c of the bottom cup 16. An annular rib 15 e extendsaxially upward and radially slightly inward, has a diameter less thanthat of the bearing 14 and is disposed in and projects from the groove13 d of the top cap 13; it is adapted to interfere diametrally with therib 13 e so that the ribs 13 e and 15 e assure mutual retention in theaxial direction of the top cap 13 and the bottom cap 15.

[0034] In other words, the rib 15 e also extends slightly radiallyinward in order to achieve said diametral interference with the rib 13e. The bottom cap 15 is completed by a plurality of hooks 15 f extendingaxially downward and having an end 15 g adapted to interfere with thesmall-diameter free end of the radial portion 16 c of the bottom cup 16to fasten together axially the bottom cap 15 and the bottom cup 16.

[0035] The axial rim 13 c and the annular rib 15 b form a chicane sealpreventing penetration of water or pollutants into the suspension thrustbearing. Similarly the rib 13 e forms a chicane seal with the rib 15 e.

[0036] What is more, the external cylindrical surface 15 c of the bottomcap 15 can be provided with an annular bead extending outward and havinga diameter in the free state greater than that of the bore in thecylindrical portion 16 b of the bottom cup 16 to assure, in addition tothe hooking action of the hooks 15 f, a force-fitting action and acentering effect through contact between the bead and the bore of saidcylindrical portion 16 b of the bottom cup 16.

[0037] Accordingly, the bearing 14 equipped with the top cap 13 andbottom cap 15 forms a subassembly whose component parts cannot be lostaccidentally thanks to the axial fastening effect of the diametralinterference between the rib 15 e of the bottom cap 15 and the rib 13 eof the top cap 13. Said subassembly, completed by the bottom cup 16, isagain protected against loss of components by the axial and radialfastening effect of the hooks 15 f of the bottom cap 15 cooperating withthe bottom surface of the radial portion 16 c of the bottom cup 16 andthanks to the bead 15 h being in contact with the bore in thecylindrical portion 16 b of the bottom cup 16.

[0038] Finally, the subassembly formed by the bearing 14, the top cap 13and the bottom cap 15, and where applicable the bottom cup 16, formswhen mounted in the top cup 4 an assembly protected against loss ofcomponents during manipulation preceding final mounting. The top cup 4and the sleeve 9 will be fastened to the elastic support block 2 thatcan be molded onto said top cup 4 and to the sleeve 9 disposed insidethe elastic support block 2.

[0039] The invention therefore provides a complete subassembly,including the thrust bearing, the top cup and the bottom cup on whichthe spring bears, that can be easily manipulated, transported andfinally mounted on the vehicle.

[0040] The embodiment shown in FIGS. 3 and 4 is similar to that shown inFIGS. 1 and 2 except that the lip 13 f of the cap 13 is replaced by arow of tongues 13 i disposed in a circular fashion and extendingradially inward so as to come into contact with the cylindrical outsidesurface 4 d of the cylindrical portion 4 c of the top cup 4. A recess 22can be provided above each tongue 13 i. The tongues 13 i are inclinedslightly downward, so that they can flex when the top cap 13 is fittedover the top cup 4, and braced against the cup 4 in the oppositedirection, so preventing axial separation of the top cap 13 and the topcup 4.

[0041] In the embodiment shown in FIGS. 5 and 6, the top cup 4 furtherincludes an intermediate annular member 23, made of sheet metal, forexample, fixed to the radial portion 4 b, for example welded to it, andhaving an L-shaped cross section with a radial portion 23 a in contactwith the radial portion 4 b and a cylindrical portion 23 b extendingaxially downward from the large diameter end of the radial portion 23 a.The bottom free edge of the rim 13 c of the top cap 13 includes anannular lip 13 j in contact with the bore in the cylindrical portion 23b of the member 23 of the top cup 4. The top surface 13 h of the top cap13 is in contact with the radial portion 23 a of the member 23. Theaxial fastening between these members is assured by the contact of thelip 13 j on the bore of the cylindrical portion 23 b.

[0042] Here the bottom cup 16 has a cylindrical rim 16 d directedupward, extending from the small-diameter end of the radial portion 16c, and disposed in a groove 15 h in the bottom cap 15. The groove 15 his radially between the hooks 15 f and the radial surface 15 d. Acylindrical portion 16 e extends downward from the large-diameter end ofthe radial portion 16 c. The spring 17 bears on the radial portion 16 cand is centered by the cylindrical portion 16 e.

[0043] The invention provides a complete subassembly including thethrust bearing, i.e. the bearing 14 plus the top cap 13 and the bottomcap 15, the bottom cup 15 and a top block formed by the top cup 4, whereapplicable equipped with the supplementary member 23, and the elasticsupport block 2.

1. A suspension thrust bearing including a first race (18), a secondrace (19), a row of rolling bodies (20) disposed between the two races,a top cap (13) in contact with the first race, and a top cup (4) incontact with the top cap, characterized in that the top cap includesintegral axial retention means for retaining the top cup.
 2. A bearingaccording to claim 1, characterized in that the axial retention means ofthe top cap include an annular lip (13 f) force-fitted over acylindrical outside surface (4 c) or a bore of the top cup.
 3. A bearingaccording to claim 1, characterized in that the axial retention means ofthe top cap include a plurality of tongues (13 g) interfering with acylindrical outside surface or a bore of the top cup.
 4. A bearingaccording to any preceding claim, characterized in that it includes abottom cap (15) in contact with the second race, said top cap includingaxial fastening means for fastening it to the bottom cap.
 5. A bearingaccording to claim 4, characterized in that the axial fastening means ofthe top cap for fastening it to the bottom cap include an annular rib(13 e) and the bottom cap is equipped with means adapted to cooperatewith the rib.
 6. A bearing according to any preceding claim,characterized in that it includes a bottom cap fastened to the secondrace and a bottom cup (16) in contact with the bottom cap, and whereinthe bottom cap includes axial fastening means for fastening it to thebottom cup.
 7. A bearing according to claim 6, characterized in that theaxial fastening means of the bottom cap for fastening it to the bottomcup include a plurality of hooks (15 f) interfering with a surface ofthe bottom cup.
 8. A bearing according to any preceding claim,characterized in that the first and second races are made of thin sheetmetal.